Air-brake apparatus.



0. JOHNSON. AIR BRAKE APPARATUS.4

APPLIUATION FILED MAY 1s, 1911.

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Patented Oct. 15, 1912.

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OSCAR JGHNSON, 0E CHDCAGO, ILLINOS.

' AIB-BRAKE APPARATUS.

Specification of Letters Patent raient-eener.15,1912.

Application filed May 18, 1911. Serial No. 627,6316.

' 'to/7mm 'it 'may concern:

it known that I, OsoAn JonNson, a een of the United States, residing` at Chict fo. in the county of Cook and State ol illinois, have invented certain new and use- :lul Qimproveinents in Air-Brake Apparatus, et' which the following is a specification.

The object of this invention is 'to provide .ineens in a straight air-brake system for reducing the pressure fluid from the pressure carried in the reservoir to that used in the braiaecylinder; for returning the pressure ttluid to the engineers brake valve; and lier producing a quick release ot' thc pressure yin the brake cylinder.

ressure-reducing valves have heretofore been employed in air-brake systems, but they have been located at points remote from the brake cylinder, whereby the action of the brakes has been delayed owing to fluctuations oit pressure in the piping.

011e oit the objects of my invention is to produce a pressure reducingvalve adapted to be located close to the brake cylinder, thus making the brakes more quickly responsive to actuations of the cngincers valve.

In the accompanyintgr drawings, Figure l is a diagram illustrating` the invention as embodied in an air-brake systenn Fig. 2 is a longitudinal central section through the valve. Fig. 3 is a :fragmcntal sectional view illustrating a change in the construction.

In the embodiment which l have chosen to illustrate the invention, l is an air colnfpressor, 2 is a compressed air reservoir connected to the compressor by means of the ipe 3, 4 is an engineer-s brake valve con nected to the reservoir 2 by means of a pipe fand provided with an exhaust pipe (3, and 7 is a brake cylinder connected to the cngineei"s brake valve by means of theI brake pipe 8. It is customary to maintain a higher pressure in the reservoir 2 than it is desirable to use in the brake cylinder. 'lo rcductl the main reservoir ressnre ol say ninety pounds, to that required for the brake cylinder, s. y titty pounds, I insert a pressurereducinff valve t) in the line between the engineers brake valve and the brake cylinder. The valve 9 may bc attached directly to the brake cylinder, it sparc permits, or may be inserted in the brake pipe at a point neer the brake cylinder. i,

The pressure-reducing` valve 9 comprises a casing 10 of any suitable forni and construction, l1 being a passage conntitng the Acasing to the brnlic cylinder, and 12 being means for connecting the casing to the brake pipe. VEntendinn transversely oli' the easing 9 is a partition 13 providing a chamber lll in connnunicution with the passage l2. In the partit-ion 13 is a port 15 surrounded by a valve scat. lt. A valve stem 17 is slidably mounted in an opening 18 formed in a partition 1t) extcnd'intransversely of the casing t), and is guided at one end in an openingr Q0 ,toi-mcd in the end wall 21 ot' a sleeve 22 having.; :1 screw-threaded conncction with the easing 1t). Between the partitions 13 and 151), the valve rod 17 is provided with a valve member 23 adapted t'o bc seated upon the scat, 1t). In the par? tition t9 is formed a cylindrical chamber constitiltingn cylinder' for n piston .25

fixed to the vulve rod 1T. Iflic partition 1S) provides a hond :for one end of the cylinder 241, the other end ot saidy cylinder being open, and in connnunication with a chamber connected to the passage 11. The partitions 13 and 1S) tot-rn between them a charmber 27. The chambers 52o and 2T are in communication by means olE a suitable number of passages 28. The space between the piston and the closed end ol` the cylinder 24 is in constant communicntion with the atmosphere through a port or vent openingl).

A cap 3() has n screw thread connection with the sleeve und is provided with a vont opening; 3l. Leakage olf pressure tluid through the opening?r Lt) muy bc prevented by any suitable menus, as for example, n gland 3Q containing packing 33. Interposcd between thc gland 32 or the par titon 2l and :i projectingv portion 34. of the vulve Iod, is a coiltd Spring 3:3' which nor* Vmalty holds the valve .23 unscntctl, whereby 'lt-cc connmlnication is provided between the passages ll und t2.

Ilxtcndingr through tlic partition 13 are ont` or more ports th. nrrznurcd to be closed by a valve dish 3T lined upon a stem 38 which is slidahly mounted in a guide 39. A. spring l0 normally holds the vulve disk 37 seated.

The operation is ns follows: `lVhcn thc ln'nkts nrc to be applied. thc engineer or nlottjn'nmn operates the engincci"s brake valve lto permit the flow ot pressure liuid from thc reservoir 2 through the pipe 5 and y1; the "said valve 4 and through the pipe 8 to the passage 12 of the pressure-reducing valve. Thence the pressure fluid passes through the chamber 14, the opening 15, the chamber 27, the passages 28, the chamber 26, and the passage 11 to the brake cylinder 7. When the pressure in the brake cylfinder reaches a predetermined point, the

iuid pressure upon the piston 25 overcomes the spring and causes the valve 23 to be seated, whereby the flow of pressure fluid to the brake cylinder is cut oli.

When the brakes are to be released, the engineer or motorman operates the valve 4 to connect the brake pipe 8 with the exhaust pipe 6, whereupon the pressure iiuid in the brake pipe and the chamber 14 escapes to the atmosphere. The pressure in the chamber 14 being thereby reduced, the pressure in the chamber '27 unseats the valve disk 37 against the tension of the spring 40, whereupon the pressure iuid in the brake cylinder begins to exhaust through 11, 2c, es, 27, se, 14 12, s, i and 6. When the pressure in the chamber 26 has been somewhat reduced, the spring 35 overcomes the remaining pressure and opens the valve 23, whereupon the remainder of the pressure fluid in the brake cylinder exhausts quickly to the atmosphere.

In order that packing 15 may be dispensed w1th,"when desired, l provide in the end wall 21 of the sleeve 22 a suitable number of openings 41 which ates against the di may be closed by means of screws 42, the walls of the opening 31 also .being screwthreaded so that one of the screws 42 may be, placed therein. When it is desired to dispense with packing, the cap 30* is unscrewed from the sleeve 22, the latter unscrewed from the casing 10, the glandv 32 removed, the sleeve 22 replaced, the screws 42 removed, the cap 30 replaced,and one of the screws 42 placed lin the opening 31. The interior of the cap 30 will then be in communication with `the chamber 14.' `With the parts so arranged, the spring 35 opereerence between theluid pressuresv on the piston 25 and the end of the valve rod 17. 1

It has been heretofore proposed to locate the pressure-reducing valve between the source of high-pressure fluid and the engineers brake-valve. ,This arrangement, however, necessitates the provision of a special reservoir to contain the `fluid of reduced vpressure,--a necessity which l obviate by locating the pressure-reducing valve closing the second mentioned valve,

for the valve rod A between the. engineers valve andthe brake l cylinder.

It will be observed that the pressure-reducing valve is adaptedto permit the return of the ressure Huid through said valve to the engineers brake valve, where the. escape'of the exhaust aords a valuable indication to the operator. A

Iclaim as my invention:

Lin air-brake apparatus, the` combination of a source of high-pressure, an eng1- neers brakev valve connected to said source of high pressure and having an exhaust outlet, a brake cylinder, a brake pipe connect# ing the engineers brake valve to said brake cylinder; a valve in said brake pipe, means? tending to hold the second mentioned valve open, pressure-fluid actuated means for the casing for the latter valve containing an outlet for pressure fluid in the brake cylinder to the brake pipe, and means within said casing responsive to pressure in the brakecylinder for opening said outlet.

2. ln air-brake apparatus, the combination of a brake cylinder, an air pipe, a valve casing having therein a chamber connected- 'to said air pipe, and another chamber con nected to said brake cylinder, a valve member for closing communications chambers, a spring tending to unseat Said' valve member, means responsive to pressure in the brake cylinder for Seating said valve, and means for relieving pressure in brake cylinder so as to permit the spring to unseatsaid valve member.

3. In air-brake apparatus, the-combina-- tion of a brake cylinder, an air pipe, a valve casing having therein a chamber connected to said air pipe and another chamber conm necte'd to said brake cylinder, a valve member for closing communications between said chambers, a spring tending 'to unseat said valve member, means responsive to in testimony whereof ailix my signature in presence of two witnessese v OSCAR dllflhlON. Vitnesses:

C. PAUL' Pessina, Gfnonsiiv L. CHINDAHL.

between said the " pressure in the brake cylinder' for' seating l lll) 

